Pinkie Pie was Derpy's best friend a couple years ago, they would go to concerts together. It was all fine up until the last concert they went to, the concert that ended their best friendship, the concert where Pinkie met 4 of her new best friends. Now years later Derpy is changing drastically, the biggest secret she has will be coming out to show itself, and there is nothing no pony can do to stop her.

Edit: Woah! How long has it been since I updated this? Oh well, there shall be a lot of editing, not really liking the whole reference to Misao and Mad Father, might just be original for once and create my own being. Plus I changed the name from "The Breaking of a Derpy Mare" just because it didn't seem right anymore, oh well toodles.